All skeletal muscles throughout the human body comprise an anatomical arc structure. See Faith and Fat Loss by Ron Williams, RTW Publishing International; First edition, 2009, incorporated herein in its entirety. This arc structure permits the muscle to contract and relax to achieve desired skeletal movements. The majority of muscles in the body are attached or anchored by ligaments and tendons to one or more stable skeletal bones and one or more mobile bones. The mobile bones are moved relative to the stable skeletal bones as the muscle is contracted and extended.
The chest muscles (i.e. pectoralis major and minor) are connected to the sternum, the clavicle, and the upper humerus, thereby forming an arc structure for these muscles. The chest muscles are contracted and extended to move the mobile, upper humerus bone with respect to the stable positions of the sternum and clavicle bones. The ball and socket anatomy of the shoulder joint comprises an extensive range of motion which permits medial and lateral rotation of the humerus. The chest muscles are contracted as the humerus adducts and rotates medially or internally towards the sternum. Conversely, the chest muscles are extended or relaxed as the humerus abducts and rotates laterally or outwardly away from the sternum. Based on this anatomy, maximum chest development is achieved when the chest muscles are optimally contracted and extended as part of a weight training activity. Maximum chest development is further achieved when weight training activities account for, and utilize the anatomical arc structure of the chest muscles.
Weight training or weight lifting is a common type of strength training for developing the strength and size of skeletal muscles. Weight training uses the weight force of gravity to oppose the force generated by muscle through concentric or eccentric contraction. Weight training uses a variety of specialized equipment to target specific muscle groups and types of movement.
Weight training may be performed using various types of equipment. In some instances, weight training is performed using free-weights. A free-weight can be classified as any object or device that can be moved freely in three-dimensional space. Examples of common free-weights include dumbbells, barbells, high/low or adjustable pulley systems, lat pull-down and low row devices, medicine balls, kettle bells, ankle weights, and the human body. In reality, any object that is free to move in three-dimensional space that is not fixed to any specific set of axis can be considered a free-weight.
Weight training may also be performed using an exercise machine. Unlike free-weights, an exercise machine is designed to limit the biomechanical motion of a portion of a user's body to one or two-dimensions. In this way, the exercise machine may focus the resistance and efforts of the user to an isolated muscle, or group of muscles.
Exercise machines use gravity, friction, tension, compression, and/or hydraulic forces to provide isolated resistance to the user. Exercise machines further provide optimized biomechanical movement and resistance for the user's body by incorporating various combinations of cables, cams, springs, elastomeric bands, hydraulic cylinders, levers, and pulleys into the machine's design. Exercise machine are thus specifically designed to provide exact, repeatable biomechanical motions that are calculated to optimize desired muscular development. In theory, any user that performs weight training on an exercise machine will achieve the muscular development for which the exercise machine was specifically designed.
Despite the general benefits of exercise machines, currently available devices have a number of shortcomings that result in less effective muscular development and potential joint and muscular injury to the user. For example, some exercise machines fail to consider and provide correct anatomical joint motion for the user. Some machines further fail to consider the structural anatomy of the targeted muscle group to optimally contract and extend the muscles for maximum efficiency and development.
As a specific example, some currently available exercise machines for developing the chest muscles fail to consider and address the correct anatomical joint motion of the shoulder and torso. This failure in design results in joint sheering as the user is required to apply or resist a force for which the targeted muscle group or the corresponding joints are not properly aligned. Joint sheering may cause tissue scaring, tearing of the muscle tissue, and/or injury to the joint, tendons, and ligaments. The resultant pain and inflammation associated with these types of injuries may result in decreased physical ability of the user, arthritis, and many other types of muscle and joint injuries. These types of injuries may also cause or exacerbate poor posture of the user. In response to the pain, the user is forced to compromise their form and body position thereby reducing the effectiveness of the exercise, and potentially leading to additional and/or long-term injuries.
Some machines further fail to reduce or correct ballistic movements and stresses that are experienced by the user when using an exercise machine. Ballistic movement and stresses on weight stack machines occur as the user utilized inappropriate or uncontrolled movements while using the machine. This may be caused by lack of proper knowledge in using the machine, incorrect selection of weight, or excess resistance. Ballistic stresses create non-fluid movement for the user and machine which may lead to muscular stresses and damage. The non-fluid movements present an undesirable feeling or sensation for the usability of the machine which may lead the user to avoid use thereof.
Thus, while exercise machines for developing the skeletal muscles are available, challenges still exist. Accordingly, there is a need in the art for an improved exercise machine that overcomes the current challenges. Such a device is disclosed herein.